That's despite the agency's earlier conclusion, reached during the Obama administration, that this pesticide could pose risks to consumers. It's a signal that toxic chemicals will face less restrictive regulation by the Trump administration.

Environmentalists love "cover crops." These are plants that tolerate cool weather and grow on farm fields after the crops are harvested. They hold the soil in place and are probably the most effective way to keep nutrients infields, rather than polluting nearby streams.

Two years ago, a U.N.-sponsored scientific agency declared that the popular weedkiller glyphosate probably causes cancer. That finding from the International Agency for Research on Cancer caused an international uproar. Monsanto, the company that invented glyphosate and still sells most of it, unleashed a fierce campaign to discredit the IARC's conclusions.

The way environmentalist Craig Cox sees it, streams and rivers across much of the country are suffering from the side effects of growing our food. Yet the people responsible for that pollution, America's farmers, are fighting any hint of regulation to prevent it.

"The leading problems are driven by fertilizer and manure runoff from farm operations," says Cox, who is the Environmental Working Group's top expert on agriculture.

He's always been obsessed with flowers and trees. As a boy, he planted so much greenery in his mother's backyard, there was hardly room to walk.

But in his thirties, he started planting cocoa trees, with their colorful pods full of magical seeds. "Something told me, just keep planting, because nobody has it! It's so strange, nobody has it!," he recalls.

The system that delivers fresh salad greens like clockwork to the nation's grocery stores is breaking down slightly. In about three weeks, consumers may get a reminder of two things. First, vegetables really are fragile living things, and most of them have to survive outdoors. Second, we depend to a remarkable degree on just a few places to grow them. (That's a lesson U.K. lettuce lovers also recently got.)

The other day, in Puerto Rico, I stumbled across one small piece of an agricultural revolution. It didn't look all that revolutionary — just an abandoned sugar plantation where workers are clearing away a mass of grass, bushes and trees in order to create better pasture for cattle.